This invention relates to a method of utilizing a three-way valve to provide simplified servicing to a refrigerant cycle, in a manner that allows the elimination of a second valve that was required in the prior art.
Refrigerant cycles are typically utilized to compress a refrigerant, and then pass that refrigerant through a series of heat exchangers to condition a fluid. Typically, a compressor compresses a refrigerant and delivers it to a condenser at which heat is rejected. From the condenser, the refrigerant passes to an expansion device, and from the expansion device to an evaporator. At the evaporator, the refrigerant takes in heat. As an example, in an air conditioning mode, the evaporator is utilized to cool air that is being delivered into an environment. Refrigerant cycles are also utilized to heat water for a hot water supply, and for many other applications.
In the prior art, the refrigerant that circulated through the refrigerant cycle tended to be Freon, or another refrigerant that could not be exposed to the environment. Thus, strict controls were in place to reduce the likelihood of any leakage of the refrigerant into the environment. One challenge for the refrigerant cycle designer in the past occurred when refrigerant was removed or added to the system. In the prior at, a pair of service valves were utilized with one valve on each side of the expansion valve. The valves were opened to allow refrigerant to flow outwardly of the system, and a recovery system was placed onto the two valve ports such that liquid refrigerant could be removed, with a vapor being returned. This complex system was necessary to minimize any possibility of leakage.
More recently, environmentally benign refrigerant such as CO2 have been developed. With the environmentally benign refrigerants, there is little concern with regard to leakage of refrigerant to the environment.